﻿using Microsoft.Extensions.Caching.Memory;
using System;
using System.Collections.Generic;
using System.Linq;

namespace CommonDevelop.Cache.Impl
{
    public class MemoryCacheService : ICache
    {
        protected IMemoryCache _cache;
        /// <summary>
        /// 构造
        /// </summary>
        public MemoryCacheService(IMemoryCache cache)
        {
            _cache = cache;
        }
        /// <summary>
        /// 验证缓存项是否存在
        /// </summary>
        public bool Exists(string key)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            return _cache.Get(key) != null;
        }
        /// <summary>
        /// 添加缓存
        /// </summary>
        public bool Add(string key, object value, TimeSpan expiresSliding, TimeSpan expiressAbsoulte)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            if (value == null)
                throw new ArgumentNullException(nameof(value));

            _cache.Set(key, value, new MemoryCacheEntryOptions().SetSlidingExpiration(expiresSliding).SetAbsoluteExpiration(expiressAbsoulte));
            return Exists(key);
        }
        public bool AddObject(string key, object value, TimeSpan? expiresIn = null, bool isSliding = false)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            if (value == null)
                throw new ArgumentNullException(nameof(value));

            if (expiresIn.HasValue)                
            {
                if (isSliding)
                    _cache.Set(key, value, new MemoryCacheEntryOptions().SetSlidingExpiration(expiresIn.Value));
                else
                    _cache.Set(key, value, new MemoryCacheEntryOptions().SetAbsoluteExpiration(expiresIn.Value));
            }
            else
                _cache.Set(key, value);

            return Exists(key);
        }
        public bool AddString(string key, string value, TimeSpan? expiresIn = null, bool isSliding = false)
        {
            return AddObject(key, value, expiresIn, isSliding);
        }        
        /// <summary>
        /// 删除缓存
        /// </summary>
        public bool Remove(string key)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            _cache.Remove(key);
            return !Exists(key);
        }
        /// <summary>
        /// 批量删除缓存
        /// </summary>
        public void RemoveAll(IEnumerable<string> keys)
        {
            if (keys == null)
                throw new ArgumentNullException(nameof(keys));

            keys.ToList().ForEach(item => _cache.Remove(item));
        }
        /// <summary>
        /// 获取缓存
        /// </summary>
        public string Get(string key)
        {
            return _cache.Get(key)?.ToString();
        }
        public T Get<T>(string key) where T : class
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            return _cache.Get(key) as T;
        }
        public IDictionary<string, object> GetAll(IEnumerable<string> keys)
        {
            if (keys == null)
                throw new ArgumentNullException(nameof(keys));

            var dict = new Dictionary<string, object>();
            keys.ToList().ForEach(item => dict.Add(item, _cache.Get(item)));
            return dict;
        }
        /// <summary>
        /// 修改缓存
        /// </summary>
        public bool Replace(string key, object value)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            if (value == null)
                throw new ArgumentNullException(nameof(value));

            if (Exists(key))
                if (!Remove(key)) return false;

            return AddObject(key, value);
        }
        /// <summary>
        /// 修改缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">新的缓存Value</param>
        /// <param name="expiresSliding">滑动过期时长（如果在过期时间内有操作，则以当前时间点延长过期时间）</param>
        /// <param name="expiressAbsoulte">绝对过期时长</param>
        /// <returns></returns>
        public bool Replace(string key, object value, TimeSpan expiresSliding, TimeSpan expiressAbsoulte)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            if (value == null)
                throw new ArgumentNullException(nameof(value));

            if (Exists(key))
                if (!Remove(key))
                    return false;

            return Add(key, value, expiresSliding, expiressAbsoulte);
        }
        /// <summary>
        /// 修改缓存
        /// </summary>
        /// <param name="key">缓存Key</param>
        /// <param name="value">新的缓存Value</param>
        /// <param name="expiresIn">缓存时长</param>
        /// <param name="isSliding">是否滑动过期（如果在过期时间内有操作，则以当前时间点延长过期时间）</param>
        /// <returns></returns>
        public bool Replace(string key, object value, TimeSpan expiresIn, bool isSliding = false)
        {
            if (key == null)
                throw new ArgumentNullException(nameof(key));

            if (value == null)
                throw new ArgumentNullException(nameof(value));

            if (Exists(key))
                if (!Remove(key))
                    return false;

            return AddObject(key, value, expiresIn, isSliding);
        }

        #region IDisposable Members

        private volatile bool disposed = false;
        private void Dispose(bool disposing)
        {
            if (!this.disposed)
            {
                if (disposing)
                {
                    if (_cache != null)
                        _cache.Dispose();
                }
                disposed = true;
            }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        ~MemoryCacheService()
            => Dispose(false);
        
        #endregion
    }
}
